Explanation

• A spectrum of light is the distribution of light into its individual colours.
• Typically displayed in the order of red, orange, yellow, green, blue, indigo, and violet (ROYGBIV).
• This is often seen in the form of a rainbow or produced through the use of a prism.

Explanation

• Nuclear energy is a form of energy that is stored in the nucleus of an atom of an element.
• It is the energy that holds the protons and neutrons together in the nucleus.
• It can be released through nuclear reactions such as fission or fusion.

Explanation

• Acceleration is not a base quantity.

The base quantities are:

• Length (L)
• Mass (M)
• Time (T)

Explanation

The molecules of a gas are in constant, random, and chaotic motion.

They move in all possible directions in three dimensions. 

Gas molecules:

• Are widely separated
• Have low attractive forces
• Are free to move in any direction
• Collide with one another

Explanation

1 kg = 1000 g

So 4 kg = 4 x 1000 g = 4000 g.

Explanation

• The speed of sound is maximum in gold, with a value of approximately 3240 meters per second (m/s).

The speed of sound in different materials:

• Air: 332 m/s
• Sea water: 1530 m/s
• Lead: 2160 m/s
• Gold: 3240 m/s
• Brick: 3650 m/s
• Copper: 4760 m/s
• Glass: 5100 m/s
• Aluminium: 6420 m/s

Explanation

According to the positions of effort, fulcrum, and load, levers are divided into three kinds:

1. First kind of lever: The fulcrum is located between the effort and the load. Examples: See-saws, crowbars, hammer claws, scissors, pliers and boat oars.
2. Second kind of lever: The load is located between the effort and the fulcrum. Examples: Bottle opener, wheelbarrow, nut cracker, nail clippers, nail cutter, paper cutter and door.
3. Third kind of lever: The effort is located between the fulcrum and the load. Examples: Broom, tongs, human arm, stapler, fishing rod and tweezers.

Explanation

In p-type semiconductors, a trivalent impurity is added, typically Boron.

Explanation

• Friction is a force that opposes motion between two surfaces that are in contact.
• It acts in the opposite direction of motion, making it harder to move an object or keep it moving.

Explanation

• The Earth completes a day in a Solar day, which is approximately 24 hours.
• This is the time it takes the Earth to rotate once on its axis, causing day and night to cycle.